I’ve had OS/2 running in a virtual machine for years; specifically, a Virtual PC one. But I’ve always known that OS/2 has idiosyncracies, such that it won’t run in VMWare (although it’s getting better in VirtualBox).

By change I stumbled on the excellent site OS/2 Museum. The whole site is fascinating, and if you’re interested in the history of OS/2, or Windows, for that matter, it is a great read.